Last Friday in New Hampshire, Jeff Flake—the outgoing Republican senator from Arizona who has denounced President Donald Trump as a threat to American democracy—got a standing ovation in Manchester, New Hampshire. John Kasich, another potential challenger to Trump in the 2020 GOP primary, will visit the Granite State next month. “The unusual flurry of activity,” notedTheWashington Post, “is stoking speculation about whether a sitting president could face a serious challenge from within his own party for the first time in a quarter-century.”

The focus on New Hampshire makes sense. It was in New Hampshire that Eugene McCarthy won 42 percent of the Democratic primary vote in 1968 against Lyndon Johnson. It was in New Hampshire that Pat Buchanan won 37 percent in 1992 against George H.W. Bush. Iowa, which traditionally holds its caucuses eight days before New Hampshire’s primary, is almost certainly too conservative to embrace a comparative moderate like Flake or Kasich. In 2016, Kasich came in eighth in the state. So is South Carolina, which in recent cycles has directly followed New Hampshire, and where Kasich came in fifth.

New Hampshire, with its libertarian bent and reputation for Yankee high-mindedness, would appear more fertile ground. But it is probably isn’t. The core reason is that most Republicans in New Hampshire—like most Republicans everywhere—like Trump. A February poll by the University of New Hampshire found that 80 percent of New Hampshire Republicans approve of the job Trump is doing as president. Among Republicans nationally, according to the most recent Gallup survey, the figure is 82 percent. And in New Hampshire, as in the nation, Republican politicians are following Republican voters. New Hampshire’s Republican governor, Chris Sununu, is a Trump backer. (The state’s two senators are Democrats.)

But what about independents? Political junkies know that New Hampshire lets independents—they’re called “undeclared” in the Granite State—vote in whichever party’s primary they want. Wouldn’t they flock to a relatively centrist Republican who asked—as Flake did last Friday—to “turn away from this brand of poisonous politics”?

Probably not. Plenty of independents do vote in New Hampshire’s Republican (and Democratic) primaries. In 2016, they comprised 35 percent of the GOP primary vote. In 2012, when there was no Democratic contest to lure them, they constituted 47 percent. But while many independents vote in Republican presidential primaries, the ones who do so aren’t actually that independent. In their book, The First Primary, David Moore and Andrew Smith examined the voting behavior of New Hampshire independents. They found that 85 percent consistently supported one party or the other. Another 15 percent did switch between the parties. But even this overstated their influence, because these true independents voted at lower rates. The vast majority of independents who vote in New Hampshire’s Republican primary, in other words, are functional Republicans.

Which helps explain why, in past New Hampshire Republican primaries, registered Republicans and independents have usually backed the same candidate. In 2016, Trump beat Kasich, who finished second, by 17 points among registered Republicans and 23 points among independents. In 2008, John McCain beat Mitt Romney by four points among Republicans and eight points among independents. Even in 2000, when McCain beat George W. Bush by a whopping 42 points among independents, he still beat him by eight points among Republicans.

There’s one recent exception to this pattern. It’s 2012, when Romney beat Ron Paul by 34 points among Republicans but lost to Paul by one point among independents. But there was no Democratic contest that year, which likely led more Democratic-leaning independents to vote in the GOP primary. (And to disproportionately back Ron Paul, who had vocally opposed the Iraq War.) If large numbers of Democratic-leaning independents vote in New Hampshire’s 2020 Republican primary, they could boost Kasich or Flake. But since the Democrats will be holding their own hotly contested primary that year, that kind of mass crossover is unlikely. After all, Democratic-leaning New Hampshire independents could have dipped into the Republican primary to vote against Trump in 2016. The numbers suggest that few did.

The bald truth is this: In this highly partisan age, people overwhelmingly stick with their party. And right now, Donald Trump is the Republican Party. There’s an elite anti-Trump constituency among some conservative pundits and politicos. But there’s no mass anti-Trump constituency among Republican (or Republican-leaning independent) voters. If there were, Jeff Flake would be cruising to reelection in Arizona right now.

That’s why the 1968 and 1992 analogies don’t hold. Eugene McCarthy won 42 percent in New Hampshire’s Democratic primary because Lyndon Johnson was overseeing a war in Vietnam that many Democratic voters loathed. Pat Buchanan won 37 percent because George H.W. Bush—never a particularly popular figure among grassroots Republicans to begin with—had reneged on his pledge to not raise taxes. (Buchanan also benefited from an early 1990s recession that hit New Hampshire hard). Johnson and Bush were vulnerable because large chunks of their party’s base felt betrayed. Ordinary Republicans don’t feel that way about Trump. To the contrary, they think he’s doing a great job.

Of course, external factors could change that. The economy could collapse. Robert Mueller—or the press—could unearth a scandal mammoth enough to shake Republican voters’ faith in Trump. (Though that would require Fox News to cover it.) But absent some exogenous event, Kasich or Flake or some other GOP presidential challenger will be fishing among the roughly 20 percent of the New Hampshire Republican electorate that disapproves of Trump. Even if they exceed that figure, it’s hard to see them reaching the standard set by McCarthy or Buchanan. And that’s in New Hampshire, the early Republican primary state that should be friendliest to an anti-Trump challenge. In hyper-conservative Iowa and South Carolina, Kasich and Flake would likely do worse.

Since the moment Trump announced his presidential candidacy, commentators have been eagerly awaiting the moment when rank and file Republicans abandon him. It hasn’t happened. And, as of now, there’s little evidence it will happen in 2020. If Democrats want to defeat Trump, they’ll have to do so on their own.